Conventionally, electronic equipment, such as a personal computer includes a keyboard unit as an input device. Usually, auxiliary input means, such as a mouse, a track ball, a touch pad, or a stick pointing device, is used together with the keyboard unit in order to move indicators, such as a cursor or an icon displayed on a screen in a display unit, and to perform operations, such as a selection or an execution by clicking or double clicking the pointing device.
In recent years, the touch pad has been widely used as a pointing device for a personal computer due to its operability. The touch pad can easily move a displayed pointer on a screen for a personal computer by moving a finger of a user in a desired direction to move the pointer with touching a surface of the pad.
Usually, a touch pad is positioned in an armrest portion of a main body of a personal computer, i.e., in front of the keyboard unit of the personal computer. Accordingly, it is not uncommon for a user to accidentally contact the touch pad surface during keyboard input operations. By such accidental contact, a cursor may easily move in an unintended direction.
In order to prevent the unintended movement of the cursor from occurring, various techniques have been proposed for prohibiting input operation from a touch pad by using utility software. For example, Japanese Application Publication 10-133796, published May 22, 1998, discloses a technique for allowing input operation from a touch pad only when no keyboard input operation is detected during a predetermined time interval. However, this technique has a problem. Specifically, when no keyboard operation is detected for the predetermined time interval, the pointer may be unintentionally moved due to static electric charge on the user, even though the user has not touched the pad.
Further, Japanese Application Publication 2001-306246, published Nov. 2, 2001, discloses a technique for providing a special button in a portion of the touch pad for selectively enabling the input from a touch pad. However, this technique also has a problem that a user must touch the special button even when a usual pad operation since the button has another function for instructing permission or prohibition of a signal input into the button unit which determines the touch pad operation. This technique has another problem that a careless input operation from the button will be accomplished since the switching of the permission and prohibition are performed by a stroke of the button part.